How Many Days Until My Birthday? (Step by Step)
Find the exact days to your next birthday, including the tricky case where this year's date has already passed.
Lena Hoffmann · 4 min read
Guides & tutorials
Practical guides, how-tos and comparisons to get the most out of our free online tools.
July 8, 2025
How Exponents Work: Powers and the Laws of Exponents
An exponent is repeated multiplication. Learn the laws of exponents, what negative and fractional powers mean, and why anything to the zero is one.
Lena Hoffmann · 3 min read
July 7, 2025
How Fast Do You Read? Average Reading Speed and How to Measure It
Most adults read prose at about 200-250 words per minute. Learn what a normal reading speed is, how to measure yours in a minute, and why comprehension matters more than raw speed.
Daniel Okonkwo · 4 min read
July 4, 2025
MB, GB, TB: 1024 vs 1000, Bits vs Bytes Explained
Understand data units clearly: the 1024-vs-1000 split, bits versus bytes, and why a 1 TB drive shows as roughly 931 GB — with real file and storage sizes.
Daniel Okonkwo · 3 min read
July 3, 2025
How to Calculate Percent Error: The Accuracy Formula for Science
Percent error tells you how close a measurement is to the true value. Learn the formula, work through an example, and see how scientists use it to judge accuracy.
Lena Hoffmann · 3 min read
July 2, 2025
Markdown Task Lists and What Actually Renders Where
Task lists are not in CommonMark. They are a GitHub Flavored Markdown extension, which is why the same file shows checkboxes in one place and literal brackets in another. The exact marker rule, what nesting does, and a table of what is CommonMark, what is GFM and what is neither — checked against both specs and four renderers.
Daniel Okonkwo · 11 min read
What Is a URL Slug? Why Lowercase, Hyphenated, and Good for SEO
A URL slug is the readable, hyphenated part of a web address that names a page. Learn why slugs are lowercase, how they help SEO, and how to generate one from a title.
Daniel Okonkwo · 3 min read
July 1, 2025
Where a Line May Break: The Unicode Algorithm Behind Every Wrapped Paragraph
"Break at spaces" fails in most of the world's writing systems. UAX #14 gives every character a line-break class; we looked ours up in Unicode 17.0.0 and ran a conforming implementation over no-break spaces, soft hyphens, zero-width spaces, URLs, Japanese and Thai.
Daniel Okonkwo · 13 min read
Square Feet to Square Meters: Factor 0.0929 and Room Sizes
Convert square feet to square meters and back with the exact factor 0.0929, worked room-size examples in both units, and why area factors are the square of length factors.
Daniel Okonkwo · 3 min read
June 30, 2025
Converting Between List Formats Without Losing Data: The Quoting Rules Nobody Reads
Turning a newline list into a comma list is trivial until an item contains a comma. RFC 4180's quoting rules, why a CSV field may contain a newline, why European spreadsheets use the semicolon, and what an empty item does to a round trip — every case run and printed.
Daniel Okonkwo · 13 min read
June 27, 2025
How Much to Feed Your Dog: Portions by Weight and Activity
How much food a dog needs depends on body weight, age and activity level. Learn how to estimate daily portions from the bag's calorie count — and why your vet is the final word.
Marco Bianchi · 3 min read
June 26, 2025
Paying Off a Loan Early: What Actually Changes
An overpayment earns exactly the loan's rate, risk-free and after tax. On $200,000 at 5.00 percent over 25 years, $20,000 paid at the start saves $42,092 of interest; the same sum at year 16 saves $11,088; applied to the payment instead of the term it saves only $15,075.
Camille Laurent · 17 min read